Process of insulating electric conductors.



To all whom it may concern.-

, WNITED I STATES PATENT oEEIo GEORGE H. RUPLEY, scHENEorADY, NEW YORK, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PROCESS OF INSULATING ELECTRIC CONDUCTORS.

Be it known that I, GEORGE H. RUPLEY, a citizen of the United States, residing at Schen ectady, county of Schenectady, Stateof New York, have invented certain new and useful Improvements in Processes of Insulating Electric Conductors, of which the following is a specification.

tates another hardening, it is evident that This invention relates to electric conductors; and its object is to provide them with a coating of insulating enamel com osed of a baked solution of the residuum resu ting from the destructive distillation of a vegetable oil.

While the process of obtaining this enamel does not form the subject-matter of this application, it may be briefly stated to consist in mixing metallic oxids with linseed-oil or the like, boiling the mixture almost to the point of insolubility, fluxing it with a refractorysolvent, as rosin-oil, reboiling until it again approaches insolubility, dissolving this residiuumin rosin-oil, turpentine, coal-tar oil, or some other volatile solvent, coating the conductor with a thin film of the solution, and baking at a high temperature to harden this film. The film is then a plied to the conductor in'the manner descri ed in the patent to Clark and Rupley, No. 687,517, November 26, 1901. The wires are then run up through the hardening-ovens. If more than one layer is applied, the wires are brought down tobe again coated and then'pass up through the oven. As each successive coating necessithe first layer is subjected to a longer baking than the second, while this in turn is baked longer than the third, and so on. The natural result of this would be a film whoseinner layer or layers are harder than the outer layer or' layers. It is desirable to prevent this undue hardening of the first coat caused by the subse uent baking in ap' lying multile coats, an it is the object o my present lnvention to eifect this result by producing.

a tough and elastic insulating coating which is homogeneous when hardened.

Inpracticing my process the wire is. first coated with a solutlon made, as above set forth, but having added to it a large proportion of a fixedoil, such as heavy rosin-oil,

amounting to, say, twenty-five per cent. by volume, of the enamel. Instead of the IOSlIloil I may use about fifty per cent. of linseedoil, cotton-seed oil, or the like, preferably Specification of Letters Patent. 7

. Application filed March 1,1905. semi No. 247,899.

Patented Dec. 5, 1905.

thickened by boiling without the addition of oxids. This'large proportion of oil retards the hardening of the first layer, so that the Wire may receive a plurality of bakings. The

subsequent layers, applied successively after the several bakings, consist, preferably, of the usual enamel solution, though the inner layers may, if desired, be made to harden less ra idly by adding more or less oil to the ename the proportion being reduced for each successive ayer'. v This process produces an enameled conductor whose insulating-film is com osed of Fy softer and more flexible than the outer, the latter being hard andglazed and durable, aflording a good protection to the layers underneath.

What I claim as new, and desire to secure by Letters Patent of the. United States, is-

1. The rocess of insulating an electric conductor w hich consists in a plying thereto successive layers of enamel aving different rates of hardening to produce a homogeneous insulation.

2. The rocess of insulating an electric conductor which consists in alternately coating the same with flexible enamel and hardening thecoating, said coatings having difierent rates of hardening whereby a homogeneous insulation is produced.

3. The rocess of insulating an electric conductor which consists in coating it with a flexible enamel, baking said coating, applying an outer layer of enamel having a more rapid rate of hardening, and subjecting the coating to another baking.

4. The process of insulating an electric conductor which consists in mixing a liquid enamel with a fixed oilto retard its rate of hardening, applying a layer of the mixture to the conductor, baking said layer, applying a layer of unmixed enamel, and again baking.

5. The rocess of'insulating an electric conductor whi der heat, mixing with said enamel a'liquid having a lower rate of hardening, applying a chconsists in providing a liquid enamel havinga given rate of hardening unfilm of the mixture to the conductor, baking said film, vapplying a film of unmixed enamel,

and again baking.

" 6. The rocess of insulating an electric con-- liich' consists in prov1d1ng a li uid' ductor -w A enamel composed of a solution of a dist ate residuum of a vegetable 011 1n a su table soloil, coating a conductor with the mixture, 10 hardening said coating, applying a coating of unmixed enamel, and again hardening.

In Witness whereof I have hereunto set my hand this 25th day of February, 1905.

GEORGE H. RUPLEY.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD. 

